The present invention relates to a thin film transistor liquid crystal display (TFT-LCD) substrate and a method for manufacturing the same.
As digital televisions become universal in recent years, conventional cathode ray tube (CRT) display devices are gradually replaced by a new generation of display devices because of its drawbacks such as non-digital configuration, large volume, heavy weight, high radiation, and the like. Typical display devices of the new generation comprise plasma display panel (PDP), organic light emitting display (OLED) and liquid crystal display (LCD), among which thin film transistor liquid crystal display (TFT-LCD) devices become more and more popular due to the merits such as lighter weight, smaller volume, lower power consumption, lower radiation, higher resolution, etc.
A TFT-LCD device comprises an array substrate and a color filter substrate facing each other with a liquid crystal layer interposed therebetween. Formed on the array substrate are gate lines, data lines, thin film transistors and pixel electrodes. The thin film transistors and the pixel electrodes can be arranged in matrix. Control signals applied to the gate lines allow for transmission of signal voltage from the data lines to the pixel electrodes, adjusting orientation of liquid crystal molecules to display a desired image. As known, the TFT-LCD device has a very complex manufacture process. If a TFT-LCD device does not meet the design specification, display quality thereof would be obviously affected. For example, coupling capacitance Cpd between a data line and a pixel electrode has a great impact on display quality. Although the value of the coupling capacitance Cpd is constant between adjacent pixels in design, there may be some deviation in actual production. Specifically, because data lines and pixel electrodes are formed in separate patterning processes with different masks, position deviations are likely to happen to the data lines and the pixel electrodes, causing the coupling capacitance Cpd to vary in some regions. If all pixel electrodes in one pixel column deviate from the designed position toward a side, coupling capacitance Cpd in each pixel region in the pixel column becomes smaller or larger, leading to darker or brighter display. In this case, the image is displayed non-uniformly in brightness, resulting in black or white belt-like mura.